Fix a problem with blocks that need to be split twice.

The code could search past the end of the basic block when there was
already a constant pool entry after the block.

Test case with giant basic block in SingleSource/UnitTests/Vector/constpool.c

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155753 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 896955170a5e405a58b82ace8b8126361ed07164..3e4e732ddb9d497393635533ea899cca2292b297 100644 (file)
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -1301,9 +1301,10 @@ void ARMConstantIslands::createNewWater(unsigned CPUserIndex,
   // pool entries following this block; only the last one is in the water list.
   // Back past any possible branches (allow for a conditional and a maximally
   // long unconditional).
-  if (BaseInsertOffset >= BBInfo[UserMBB->getNumber()+1].Offset)
-    BaseInsertOffset = BBInfo[UserMBB->getNumber()+1].Offset -
-      (isThumb1 ? 6 : 8);
+  if (BaseInsertOffset + 8 >= UserBBI.postOffset()) {
+    BaseInsertOffset = UserBBI.postOffset() - UPad - 8;
+    DEBUG(dbgs() << format("Move inside block: %#x\n", BaseInsertOffset));
+  }
   unsigned EndInsertOffset = BaseInsertOffset + 4 + UPad +
     CPEMI->getOperand(2).getImm();
   MachineBasicBlock::iterator MI = UserMI;
@@ -1315,6 +1316,7 @@ void ARMConstantIslands::createNewWater(unsigned CPUserIndex,
        Offset < BaseInsertOffset;
        Offset += TII->GetInstSizeInBytes(MI),
        MI = llvm::next(MI)) {
+    assert(MI != UserMBB->end() && "Fell off end of block");
     if (CPUIndex < NumCPUsers && CPUsers[CPUIndex].MI == MI) {
       CPUser &U = CPUsers[CPUIndex];
       if (!isOffsetInRange(Offset, EndInsertOffset, U)) {